JPH0767698B2 - Epoxy resin mold and manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to plastic molding such as compression molding, transfer molding, injection molding, vacuum molding, and press molding of metal plates for plastics and filler-containing plastics. The present invention relates to an epoxy resin molding die having excellent durability, which is particularly suitable for an injection molding die having a high molding pressure, when it is molded by another method.

(Prior Art) Metals centering on iron have been generally used for plastic molding dies such as injection molding and vacuum molding. However, since the metal mold is not easy to cut,
It has the drawback that the cost is high and the processing takes a long time. To overcome the drawbacks of this metal mold,
Materials such as aluminum and zinc alloys having good workability have been developed. A mold using such a new metal material is not an essential solution because it goes through the same manufacturing process as an iron mold.

Therefore, it has been desired to replace the metal mold with a resin mold that is easy to process and can greatly simplify the mold manufacturing process. Thermosetting resins such as epoxy resins, urethane resins, and silicone resins have been used as such resin mold materials. Of these, the epoxy resin is considered to be the most suitable as a mold material because of its good curability and performance of the cured product.

(Problems to be solved by the invention) However, conventional epoxy resin materials for molds are not satisfactory in workability and performance of cured products, especially durability which can be said to be life of the mold, and at most trial manufacture in plastic molding or press molding. It was only given the status as a mold.

From the viewpoint of casting work and defoaming work, the necessary conditions in the mold manufacturing process work are that the viscosity of the compounded product is below a certain value, that the working time is long, and problems such as deformation of the master model The heating temperature may be 60 ° C. or lower. However, the conventional epoxy resin compound for mold has a high viscosity, the pot life is short, and the heating temperature until the mold release is higher than 60 ° C.

Further, among the properties of the cured product, heat resistance and thermal shock resistance related to the durability of the mold are important. Of these, heat resistance is at least 15
0 ° C or higher is required. Further, heat resistance and impact resistance are required to pass at least twice in a washer-embedded cold heat test at a temperature of -20 ° C to 120 ° C. However, none of the conventional epoxy resin compounds for molds have a heat resistance of 150 ° C. and a thermal shock resistance that passes the washer-embedded cold heat test twice or more.

In order to make up for such drawbacks of the epoxy resin type, JP-A-63
-278808 discloses a resin mold in which whiskers are compositely reinforced. However, it cannot be used for the production of resin molds by the casting method intended by the present invention because the viscosity of the compounded product is too high.

Further, as a conventional plastic molding die made of resin, for example, there is one shown in FIG. The molding die shown in the figure shows the case where the injection-molded product or the RIM molded product is produced on a trial basis and the mold is made of resin when a small amount of production is performed. Since the resin material used for molding has a high temperature, a thermosetting resin having heat resistance is used as the mold resin material. As a normal mold structure, a few mm on the mold surface
A resin layer 1 having a thickness of about 30 mm is provided, and a casting is used for the backup material 2.

Further, JP-A-63-270104 discloses a method for producing a resin mold using a thermosetting resin composition. However, in such conventional plastic molds made of resin, 1) the viscosity of the compounded product at the time of casting is as high as 100 to 1000 poise, defoaming is liable to be insufficient, and pinholes are easily generated on the die surface, so that the casting work It is also difficult and the resin does not flow sufficiently into the gap between the models, so the transferability is poor and it is difficult to obtain a good mold. 2) With conventional mold resin materials, the material itself tends to crack due to shrinkage during curing, and the above washer embedding test can withstand even one cycle of repeated rapid heating and cooling from -20 ° C to 120 ° C. Absent. 3) Since the primary curing temperature at which the epoxy resin compound on the molding surface can be released from the model is 60 ° C or higher, there are restrictions on the model materials. 4) To prevent cracks, it is effective to uniformly thin the resin layer to prevent stress concentration at the portion where the thickness of the resin layer changes abruptly, but the contact surface of the backup material with the mold resin layer is It is necessary to finish it in a state close to the regular mold shape surface, and in effect it is almost the same as finishing the molding surface of the mold, and it can hardly be expected to be effective in terms of shortening the number of manufacturing days and manufacturing man-hours etc. Therefore, the merit of the resin mold material as the mold could not be expected.

The resin injection molding die manufactured in this way is also prone to cracks on the mold surface due to the heat of the high temperature material resin flowing in from the gate and the thermal stress caused by forced cooling of the mold during production. The mold could only be used as a prototype for a few shots or as a very small production type.

Further, in the conventional resin mold, the cured product of the resin material for the mold is hard to be exposed to the corrosive liquid, so that the so-called transfer grain is the center. For this reason, it is impossible to apply so-called etching embossing into the designer's free design, and surface decoration on the resin mold has been performed only when there is an actual part to be transferred such as leather.

(Means for Solving the Problems) The present inventors have arrived at the present invention as a result of extensive studies for solving these problems.

That is, the present invention relates to a production epoxy resin mold having a dense epoxy resin layer as a molding surface in which metal powder is dispersed, and a method for producing the same.

The dense epoxy resin layer referred to in the present invention is a layer formed of a cured product of an epoxy resin that does not substantially have defects such as voids, and for this purpose, the epoxy resin compounded product is sufficiently defoamed, It is necessary to prevent air bubbles from entering the resin compounded product even when the compounded product is cast into a predetermined shape.

Specifically, the observation of voids can be confirmed by the naked eye or an optical microscope. Voids are those with a size of 0.1 mm or more, and those with substantial defects are 10 pieces / 100
It refers to a void amount of ³ cm ³ or more.

The epoxy resin layer referred to in the present invention is a resin layer obtained by curing a liquid epoxy resin and a liquid curing agent under predetermined curing conditions. The liquid curing agent here is selected from liquid amine curing agents or acid anhydrides.

The liquid epoxy resin here is, for example, bisphenol A.
Type epoxy resin, bisphenol F type epoxy resin, novolac phenol type epoxy resin, glycidyl amines such as tetraglycidyl dicyclohexylamine, and the like, and at least one or more epoxy resins selected from these resins. Preferably, the liquid epoxy resin is a bisphenol A type epoxy resin,
Bisphenol F type epoxy resin or tetraglycidyl dicyclohexylamine. Further, in some cases, various reactive and non-reactive diluents can be used together as a viscosity reducing agent for the epoxy resin.

Liquid amine-based curing agents include, for example, aliphatic polyamines such as diethylenetriamine and triethylenetetramine, isophoronediamine, cyclohexylamine, bis (4-amino-3-methylcyclohexyl) methane, bis (4-).
Examples thereof include alicyclic amines such as aminocyclohexyl) methane and aromatic amines such as metaxylenediamine, diaminodiphenylmethane and diaminodiphenylsulfone, and eutectic materials thereof. Preferably, the liquid amine curing agent is a eutectic mixture of diaminodiphenylmethane and bis (4-amino-3-methylcyclohexyl) methane or bis (4-aminocyclohexyl) methane.

The liquid amine curing agent of the present invention is used in the range of 0.5 to 2 equivalents of active hydrogen of amine with respect to 1 equivalent of epoxy group of epoxy resin.

Examples of the acid anhydride used in the present invention include phthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride and methylnadic acid anhydride. A curing accelerator is generally used when an acid anhydride is used.

The metal powder is used for the purpose of improving the thermal conductivity and improving the mechanical properties of the mold. As the metal powder, for example, aluminum,
Copper, iron, gold, silver, nickel, chromium and the like can be used alone or in combination. The average particle size of metal powder is 50
μm or less is preferable. If it is 50 μm or more, not only the settling of metal powder in the blended product becomes a problem, but also the durability of the mold is adversely affected. More preferably, the metal powder has an average particle diameter of 40 μm.
95/5 to 50/5 for the above and those with an average particle size of 20 μm or less
A mixture in which the weight ratio is 0 is preferable. By mixing the metal powder, it is possible to obtain a good epoxy resin cured product which is excellent in the washer-embedded thermal shock test and which does not cause sedimentation of the metal powder in the compounded product.

What is the washer-embedded thermal shock test? The shape and dimensions shown in Fig. 9 a, b, and c (l ₁ = 2.5 mm, l ₂ = 12.5 mm, l ₃ = 10 mm, l ₄
＝ 60mm, l ₅ ＝ 15mm, l ₆ ＝ 10mm, h ₁ ＝ 4mm, h ₂ ＝ 5mm) Set the nut 32 of the bolt 31 to the washer 30 as shown in the figure, and attach the bolt, nut and washer to it. The epoxy resin compounded product 33 is cast so as to be completely filled and cured under predetermined conditions. This cured product is repeatedly tested between −20 ° C. and 120 ° C. and evaluated by the number of times until the cured product cracks.

The mixing ratio of the metal powder to the epoxy resin may be such that the filling rate of the metal powder in the epoxy resin layer is 30% or more by volume.

The heat resistance of the mold is important, and in the case of a plastic mold, the heat distortion temperature (HDT) must be 150 ° C or higher. This thermal transformation temperature is a heat resistant temperature measured based on the test method of ASTM D648. The heat distortion temperature of 150 ° C. or higher can be obtained by selecting the above-mentioned epoxy resin and curing agent.

Next, a method of manufacturing the epoxy resin mold according to the first preferred embodiment of the present invention will be described.

First, an epoxy resin compounded product is prepared in advance. The epoxy resin compounded product in the present invention is obtained by mixing the epoxy resin with the metal powder using a mixer so as to be as uniform as possible, and mixing the curing agent with the metal powder. The formulation may be heated to facilitate mixing,
Careful attention must be paid to the pot life of the compounded product.

Next, (1) Assemble a frame so that the mixed product does not flow out, and set the master model on it. The master model is the target product itself or a mold of the same shape. As the material, dry wood, synthetic wood, gypsum, ABS resin, silicone resin, acrylic resin, epoxy resin, etc. are used. In general, it has low heat resistance and can retain its shape only in the temperature range of 60 ° C or lower. Further, as a special case, iron, aluminum, and copper alloy materials are used.

Further, subsequently, the following operation is performed.

(2) A release agent is applied to the surface of the master model.

(3) Sufficiently defoam the epoxy resin mixture prepared in advance, and place it above or below the master model at a temperature of 60 ° C or lower.
Pour it so that the surface shape of the model can be duplicated.

(4) Leave the whole at a temperature below 60 ° C for 1 hour to several days,
Primary cure the formulation.

(5) Remove the master model from the cured resin.

(6) The cured resin is secondarily cured at a higher temperature to obtain the target epoxy resin mold.

When defoaming and casting the epoxy resin compounded product of (3) above, it is an essential condition that the viscosity of the compounded product is low,
Viscosity at 60 ° C must be less than 100 poise.

The temperature until the master model is removed in the present invention refers to the primary curing of the epoxy resin compounded product, and in order to further improve the practical strength, a method of performing secondary curing called post cure is preferable.

Next, in the epoxy resin mold of the second preferred embodiment of the present invention, the resin compounded product is used on the surface. That is, a feature is that a dense epoxy resin layer in which the metal powder is mixed and dispersed is used on the molding surface of the molding die, and a metal is used as a backup material for the molding surface. Molds that use a resin layer on this surface are dry wood coated with a release material, gypsum,
Model made by any means of resin material, casting,
A cavity is formed for casting a resin compound for the molding surface by holding a backing material made of either a rolled metal material or a low-melting metal material so as to have a space therebetween, and the above-mentioned cavity is formed in the cavity. It can be manufactured by casting the epoxy resin compounded product and then curing it to form the surface of the molding die.

Next, the epoxy resin mold of the third preferred example of the present invention is a mold using a resin layer on the molding surface similarly to the epoxy resin mold of the second example described above. As the backup material, a metal material having a so-called near net shape shape slightly offset from the shape surface of the molding die is used. This plastic mold also has a model surface made of dry wood, gypsum, or a resin material, and a metal backup material of a so-called near net shape having a surface shape slightly smaller than the model surface,
Forming a casting cavity by holding each surface shape so as to face each other so as to have a uniform and slight clearance, and after casting the epoxy resin compounded product,
It can be manufactured by curing and obtaining the surface of the mold.

When manufacturing a mold for small-volume production, the metal back-up material is a flow 100 with a rectangular cross section with a side of 1 mm to 20 mm.
mm-500 mm steel or ceramic pins made by sliding freely in the axial direction, and slightly smaller than the regular mold surface shape made of dry wood, gypsum, or resin material. After the bundle of pins is pressed against a model with a small similar shape to give the surface shape of the backup material, the bundle is fixed from the outer periphery to make a reusable casting mold, and the casting mold is melted It can be rapidly manufactured by hardening the metal material, so-called molten metal, after casting.

Further, the resin mold of the fourth preferred embodiment of the present invention is a mold using a resin layer in which the metal powder is dispersed on the molding surface, and further has a grain pattern on the molding surface. In this molding die, a thin film having a grain pattern formed by optically treating a photocurable resin is attached to a molding surface, and at least one kind of fine particles of iron, sand, glass, and ceramics is shot blasted on the thin film. It can be manufactured in the same manner as the molding die of the second example, except that the surface is decorated by spraying with a mold to form a grain pattern on the molding surface.

Polyethylene, polypropylene, polystyrene, general-purpose plastics such as ABS resin of the present invention, nylon resin, polyester resin, polyacetal resin, injection molding, vacuum molding, blow molding of thermoplastics such as special plastics such as acrylic resin, etc. The present invention can be applied to a molding die for a thermosetting resin such as a phenol resin, a urethane resin, or an epoxy resin.

It is also useful as a press-molding die for thin metal plates such as steel plates, aluminum plates and copper plates.

(Example) Hereinafter, the present invention will be described in more detail with reference to Examples.

Example 1 (Preparation of Epoxy Resin Blend) 40 parts by weight of bisphenol A type epoxy resin AER331 (manufactured by Asahi Chemical Industry Co., Ltd.), 50 parts by weight of atomized aluminum powder having an average particle diameter of 42 μm and an average particle diameter of 10 μm 10 parts by weight of atomized aluminum powder was mixed to prepare a base compound A. Next, a curing agent A of a melt mixture of Wandamine HM (manufactured by Shin Nippon Rika Co., Ltd.) 70% by weight and diaminodiphenylmethane 30% by weight was prepared.

10 parts by weight of the curing agent A was added to 100 parts by weight of the main agent A, and both were thoroughly stirred until uniform. Immediately, the temperature of the system was raised to 50 ° C by heating. Here, the compounded product was vacuum degassed to obtain a compounded product A. The viscosity of this compounded product at 60 ° C. was 80 poise by a B-type viscometer.

(Set of master model) Prepare a 200m (L) x 200mm (W) x 100mm (H) model epoxy resin cured product, cut this surface, and form an uneven pattern with a height of 1 to 10mm on the surface Then, a master model was produced. This master model was placed with the concavo-convex pattern on top, iron plates having a height (H) of 200 mm were set in close contact with the master model on all four sides, and an outer frame for casting the molding resin was assembled. A mold release agent was applied to the surface of the master model and the inside of the outer frame.

(Production of Resin Mold) A pipe of cooling water was installed on the master model set in the outer frame, and an epoxy resin compounded product prepared in advance was poured into the pipe from above, and this was left in a drying oven at 60 ° C. for 5 hours. Thereafter, the epoxy resin compounded product which was cooled to room temperature and cured was released from the master model. After the mold release, the epoxy resin mold was left in a drying oven at 180 ° C. for 5 hours to complete the resin mold production. No void was observed on the molding surface of the obtained resin mold.

(Durability Test of Epoxy Resin Mold) After the molding resin injection port was provided in the obtained epoxy resin mold, this was used as a cavity and attached to an injection molding machine.
A zinc alloy mold was used for the core part. Using this mold, ABS resin was injection-molded at a pressure of 300 kg / cm ² and an injection temperature of 230 ° C. for 3000 shots, but there was no damage to the mold.

(Performance of Epoxy Resin Blend) The prepared epoxy resin blend was pre-cured at 60 ° C. for 5 hours and then at 180 ° C. for 5 hours to obtain an epoxy resin cured product. The performance of the cured product is shown in Table 1.

Examples 2 to 4 (Preparation of epoxy resin compound) Bisphenol F type epoxy resin Epicron 830 (manufactured by Dainippon Ink and Chemicals, abbreviated as BF resin) has an average particle diameter of 45 μm.
The atomized aluminum powder and the copper powder having an average particle size of 10 μm were added as shown in Table 2 to prepare bases B to D. Wandamine HM was added to this as a curing agent, and Compounds B to D were prepared in the same manner as in Example 1. The viscosity of the blended product at 60 ° C. is also shown in Table 2.

(Curing Performance of Blended Products) A cured product obtained by curing the blended products B to D at 60 ° C. for 5 hours and at 180 ° C. for 5 hours was prepared in the same manner as in Example 1 and its performance was examined. The results are shown in Table 3.

(Manufacture of Mold and Durability) Resin molds using the blended products B to D were manufactured in the same manner as in Example 1, and an injection molding test was performed in the same manner as in Example 1. The results are shown in Table 4.

Example 5 (Preparation of Epoxy Resin Blend) 20 parts by weight of AER331, 20 parts by weight of tetraglycidyldicyclohexylamine, and 2 parts by weight of styrene / butadiene block polymer were mixed with 60 parts by weight of copper powder having an average particle diameter of 50 μm as a base compound. E was produced. Next, 32 parts by weight of Kayahard MCD (manufactured by Nippon Kayaku Co., Ltd.) and 0.5 part by weight of 2-methylimidazole were mixed to prepare a curing agent E. 32.5 parts by weight of a curing agent was added to 100 parts by weight of the main agent E, and the mixture was uniformly mixed and vacuum defoamed to prepare a compound E. When the viscosity of the compound E was measured at 60 ° C., it was 18 poise.

(Curing performance of compounded product) The compounded product E was heated at 60 ° C for 5 hours and at 200 ° C for 5 hours to obtain a cured product. The performance was examined in the same manner as in Example 1. The results are shown in Table 5.

(Manufacturing of Mold and Durability Test) A resin mold using the compound E was manufactured in the same manner as in Example 1, and the durability test was carried out. No mold damage was observed up to 5000 shots.

Comparative Example 1 When the primary curing of the compounded product A was carried out at 100 ° C. to manufacture the mold in Example 1, the master model was deformed and a good mold could not be obtained.

Comparative Example 2 In the preparation of the epoxy resin compounded product of Example 1, after mixing the main agent A and the curing agent A, a compounded product was obtained without vacuum defoaming, and a mold was produced to obtain a resin mold with many voids. A durability test similar to that in Example 1 was conducted using this resin mold.
A crack was generated in the convex portion on the shot.

Example 6 A molding die shown in FIG. 1 was manufactured. In the illustrated mold, the cavity 8 made by curing the epoxy resin compounded product of Example 1, the resin surface layer 1 of the core 9 and the backup material 2 made of a casting holding the surface layer, and the product material. A gate 10 into which a molten resin material enters a cavity of a mold, a cooling pipe 13 through which a coolant for cooling the resin material flows, an ejector pin 12 for extruding a solidified work W inside a backup material, and an ejector pin 12 It is composed of an ejector 11 for driving.

This mold was manufactured as follows.

A model M (consisting of dry wood) was manufactured, and a release material was applied to the surface. As shown in FIG. 2, a backup material 2 manufactured by cutting a casting or a rolled metal material and a model M are fixed by holding a predetermined clearance C opposite to each other, and the outer periphery of the clearance is covered with a plate material 7 to perform sealing. It was The sealing plate 7 was provided with a plurality of casting ports 4 of compounded resin.
Further, the backup material was provided with holes 5 for deaeration. If the degassing inside the casting cavity consisting of the model, the backup material, and the plate on the outer periphery and the filling of the resin mixture for the molding are performed securely, the mounting positions of the casting port and the degassing hole are not particularly limited. Absent. Next, the epoxy resin compounded product 6 of Example 1 was cast from the casting hole. 60 ° C in the oven after casting
Then, the epoxy resin was heated for a predetermined time to primary cure the epoxy resin. 1
After the completion of the secondary curing, the mold was removed from the model and again heated in the oven for a while to perform secondary curing, and the epoxy resin was completely cured to obtain a finished product. FIG. 3 shows the state of the core that has been demolded from the model.

Next, when the ABS resin was injection-molded with the injection-molding die manufactured as described above, no crack was found on the surface of the die even when the molding of about 20,000 shots was completed.
The molding conditions are shown in Table 6.

Table 6 Material ABS resin (resin temperature 230 ° C.) Injection molding pressure 110 kg / cm ² Mold temperature 80 ° C. Example 7 A molding die shown in FIG. 4 was produced. In the molding die shown in the figure, a surface layer 1 produced by curing the epoxy resin compounded product of Example 1, a surface layer and a backup material 2 made of a low melting point alloy such as a zinc alloy cast in the shape of a near net shape are used. The resin mold which did is shown. This mold was manufactured as follows.

A model M manufactured in the same manner as in Example 6 was laminated with a sheet wax 14 having a thickness corresponding to the resin thickness of the mold surface layer as shown in FIG. I made it. As shown in FIG. 5-2, the clamp device 15,
The main casting unit U is placed in a horizontal state with the base 16 assembled. Next, the pins P made of steel or ceramic were slidably aligned and set in a casting unit.
In this example, an SK material pin having a rectangular cross section with one side of 1 mm to 20 mm and having the same length was used, but the material is not particularly limited as long as it is a heat resistant and reusable material. The casting unit and the backup similar model were matched, and the pins were slid to provide the backup shape surface 3. When the shape surface is determined, the bolt 17 of the clamp device is tightened to fix the pin. Next, as shown in FIG. 5-3, the casting unit was returned to the vertical state, and the molten zinc alloy Z was cast into the cavity 8 formed in the unit. When the zinc alloy was hardened, it was removed from the unit and used as a backup material. Since a mold release agent such as boron nitride is applied to the casting surface of the casting unit, the pins can be easily separated from each other without causing seizure of the zinc pin for backup and the backup zinc alloy, and the pins and the casting unit can be reused. Met.

In this example, a zinc alloy was used as the backup material, but the material is not particularly limited as long as it is a material that melts at the heat resistant temperature or lower of the pin material used in the casting unit.

Next, sheet wax was removed from the above-mentioned similar model to obtain a regular model shape, and a release material was applied to the model surface. As shown in FIG. 5-4, the backup material 2 and the model M manufactured by the above method are opposed to each other and fixed with a predetermined clearance C held, and the outer periphery of the clearance is covered with the plate material 7 for sealing. . A plurality of resin casting ports 4 are provided on the sealing plate member 7. Further, the backup material 2 was provided with holes 5 for deaeration. The epoxy resin 6 in which the curing agent was sufficiently mixed and which was sufficiently defoamed in the liquid was cast from the casting port 4. After completion of the casting, the epoxy resin was preliminarily cured by heating in an oven at 60 ° C for a predetermined time. After the temporary curing was completed, the mold and the model were released from the mold, and the mold was again heated in the oven for a while to completely cure the epoxy resin to obtain a finished product of the core shown in FIG. 5-5.

When the ABS resin was injection-molded with the injection-molding die manufactured as described above under the same conditions as in Example 6, it was about 2
No cracks were found on the mold surface even after the completion of molding for 10,000 shots.

Example 8 A molding die shown in FIG. 6 was manufactured. In the illustrated mold, a resin surface layer 1 obtained by curing and molding the epoxy resin compounded product of Example 1 and a low melting point alloy backup material 2,
It is composed of a molding surface 18 produced by sticking a thin film made of a resin having an extensibility and having a textured pattern formed by a photoresist, and spraying fine glass particles by shot blasting.

This mold was manufactured as follows.

Model M and backup material 2 manufactured in the same manner as in Example 6
Was set while maintaining a slight clearance to form a resin material casting cavity for the surface. A prescribed amount of the resin material 6 for a mold was weighed, sufficiently stirred, and then poured into the cavity. Put the whole cast mold in the oven at about 60 ° C. 5
The resin was temporarily cured by heating for a period of time and released from the model. Further, the mold was heated at 180 ° C. for 5 hours to completely cure the resin, and the entire mold was manufactured. The hardness of this epoxy resin cured product was 166 μm on the Rockwell M scale, which was a good hardness for shot blasting.

Separately from this, as shown in FIG. 7, a freely designed grain pattern 19 was photographed to produce a grain film 20. Set the grain pattern film 20 on the glass plate 22,
The cover film 21 was placed on it. Cover film 21
Apply a thin layer of photocurable resin 23 on top of the base film
It was covered with 24 and the light curing resin was cured by the light source 26. The base film had a coating film 25 coated on the contact portion with the photocurable resin. When the base film was peeled off from the cover film, an unhardened material which was masked and was not exposed adhered to the exposed portion 27 of the photocurable resin and the grain pattern film 20 on the base film. The base film was washed with water to remove the uncured portion. The entire base film was dried and then post-exposed to reinforce the base film.

Next, the base film was attached to the surface layer 1 of the epoxy resin molding die manufactured by the above means. At this time, when the surface of the base film on which the cured product of the photocurable resin adhered was brought into contact with the molding surface, the base film and the molding surface easily adhered. Next, when the base film was peeled off, the cured product of the photo-curing resin remained on the surface of the mold in the state of the embossed pattern 19 while being attached to the coating film.

Further, when the glass particles 29 are sprayed onto the mold surface by the shot blasting device 28, the portion coated with the photo-curing resin remains, and the other portions are removed by the glass particles and the grain pattern 19 is formed along the grain pattern. Decorated on the surface.

The diameter of the glass particles used for this shot blast is determined by the grain pattern, but it is generally 50 μm to 100 μm,
Good results were obtained with an injection pressure of 3 kg / mm ² and an injection distance of 100 mm to 150 mm.

After the surface was decorated, the embossed pattern was removed to obtain an epoxy resin mold having the embossed pattern.

Using the ABS resin injection molding die thus obtained, molding of about 20,000 points could be performed.

Example 9 100 parts by weight of bisphenol A type epoxy resin AER331 was mixed with 300 parts by weight of iron powder having an average particle size of 50 μm and 50 parts by weight of aluminum powder having an average particle size of 8 μm to prepare a main agent. 25 parts by weight of the curing agent A used in Example 1 was added to this, and the mixture was stirred and degassed in vacuum. This compound is poured into a casting mold consisting of a plaster model, a steel back-up material and a frame material, heated at 60 ° C for 5 hours to primary cure, and further heated at 180 ° C for 2 hours to secondary cure and punched. And the die was manufactured. The punch and die were installed in the breath device and the conditions shown in Table 7 were used.
A cold-rolled steel plate (corresponding to JIS C3141 SPCC) having a plate thickness of 0.8 mm was press-formed. Although production was performed for 1000 strokes or more, no damage or wear of the mold surface occurred.

Reference Example A compound G was prepared by adding 4 parts by weight of 2-methylimidazole instead of the curing agent A used in Example 1. The HDT of the cured product of this compounded product was 170 ° C, but cracks occurred in the first thermal shock resistance. When a resin mold was prepared in the same manner as in Example 1 and the durability was examined, the convex portion was deformed at the 10th shot.

(Effects of the Invention) As described above, the plastic molding die of the present invention uses the dense epoxy resin dispersed in the metal powder as a whole or as the molding surface, and thus the plastic molding die of the conventional epoxy resin molding die is obtained. The defects were removed and the durability was significantly improved. Also, as the surface material of the mold, it is possible to remove the mold by heating up to 60 ° C., the heat distortion temperature is 150 ° C. or higher, and a thermosetting epoxy resin composition having excellent thermal shock resistance is used,
Cracks on the molding surface of the mold can be prevented and durability can be greatly improved.

In addition, as shown in Example 7, the surface of the backup material was bundled so that a large number of steel pins having a rectangular cross section with a side of several mm were freely slidable in the axial direction, and the model was pressed to give the desired shape. Then, after fixing and casting a low melting point alloy to form a backup material with a shape of near net shape, the thickness of the mold resin material becomes constant, and a rapid change in shrinkage during resin curing is suppressed. Also from the surface, it is possible to obtain the effect of preventing the generation of cracks on the molding surface.

Conventionally, in a mold using resin for the surface layer, an intermediate layer is provided to strengthen the bond between the surface material and the backup material,
Although the work of driving minute screws into the backup material has been performed, according to the present invention, since the surface of the backup material has minute unevenness, an anchor effect is exerted between the surface resin and the surface of the backup material, and the resin layer and the backup material The bond strength of materials can be strengthened.

In addition, since the backup material surface shape is a near net shape that is close to the regular shape surface of the mold, no surface processing is required, and since a mold for casting the backup material is manufactured using bundled pins, free shape Since it can be manufactured in a short period of time and the casting mold can be reused, the manufacturing period can be shortened and the equipment cost can be reduced.

Further, as shown in Example 8, in the case where a base film having a grain pattern is manufactured with a photoresist, the base film is attached to a resin-made mold, and the surface of the resin mold is decorated by shot blasting. In, it is now possible to fold a free design equivalent to etching wrinkles into a resin mold that was not possible with conventional etching wrinkles,
The effect is that pattern confirmation can be performed from an early stage with a prototype part manufactured with a resin mold. Further, since it has a grain pattern similar to that of conventional etching, the resin mold can be applied to mass-produced parts, and the effect that it is not necessary to manufacture an expensive mold for a small-volume mold is obtained.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a molding die according to an example of the present invention, FIG. 2 is an explanatory view of production of an injection molding die according to the present invention, and FIG. 3 is a core of a model produced by injection molding after completion of demolding. Sectional view, FIG. 4 is a sectional view of a molding die according to another example of the present invention, FIG. 5-1 is a sectional view of a model with sheet wax attached, and FIG. 5-2 is a sectional view of a casting mold at a manufacturing stage. 5-3 is an explanatory view of casting of a low melting point alloy, FIG. 5-4 is an explanatory view of casting of a resin material for a mold, FIG. 5-5 is a sectional view of a core demolded from a model, FIG. 6 is a cross-sectional view of a molding die having a textured pattern on the molding surface, FIG. 7 is a process drawing of texture processing, FIG. 8 is a cross-sectional view of an injection molding die by a conventional method, and FIG. 9b is a side view of the washer of FIG. 9a, and FIG. 9c is the backside of the washer of FIG. 9a. It is. 1 ... Resin surface layer, 2 ... Backup material 3 ... Backup shape surface 4 ... Resin casting port, 5 ... Degassing hole 6 ... Epoxy resin compounded product 7 ... Sealing plate material, 8 ... Cavity 9 ... Core, 10 ... Gate 11 ... Ejector, 12 ... Ejector pin 13 ... Cooling pipe, 14 ... Sheet wax 15 ... Clamping device, 16 ... Base 17 ... Bolt, 18 …… Molding surface 19 …… Texture pattern, 20 …… Texture pattern film 21 …… Cover film, 22 …… Glass plate 23 …… Photocurable resin, 24 …… Base film 25 …… Coating film 26 …… Light source , 27 …… Photosensitive part 28 …… Shot blasting device 29 …… Glass fine particles, 30 …… Washers 31 …… Bolts, 32 …… Nuts 33 …… Epoxy resin compound products

Front Page Continuation (72) Inventor Shuichi Ishimura 1 Asahi Kasei Kogyo Co., Ltd. 2 at Samejima, Fuji City, Shizuoka Prefecture (72) Inventor Isao Takagi 1 Asahi Kasei Kogyo Co., Ltd. at 2 Samejima, Fuji City, Shizuoka (56) Reference Documents JP-A-63-302006 (JP, A) JP-A-63-270105 (JP, A) JP-A-63-202411 (JP, A) JP-A-2-245018 (JP, A)

Claims (7)

[Claims] 1. An average particle diameter of 50 μm or less and an average particle diameter
95 for particles of 40 μm or more and particles of average particle size of 20 μm or less
A molding die made of an epoxy resin, characterized in that a dense epoxy resin layer in which metal powder mixed in a weight ratio of / 5 to 50/50 is dispersed is used as a molding surface. 2. The average particle diameter is 50 μm or less, and the average particle diameter.
95 for particles of 40 μm or more and particles of average particle size of 20 μm or less
/ 5 to 50/50 epoxy resin compounded product containing a metal powder mixed in a weight ratio of 60 ° C at a viscosity of less than 100 poise,
A method for producing a molding die made of epoxy resin, which comprises degassing, filling a master model, curing at a temperature of 60 ° C. or lower, and then removing the master model. 3. The method for producing an epoxy resin mold according to claim 2, wherein after the master model is removed, the cured resin is secondarily cured at a temperature higher than 60.degree. 4. The average particle diameter is 50 μm or less, and the average particle diameter.
95 for particles of 40 μm or more and particles of average particle size of 20 μm or less
A molding die made of epoxy resin, characterized in that a dense epoxy resin layer in which metal powder mixed in a weight ratio of / 5 to 50/50 is dispersed is used as a molding surface and metal is used as a backup material. 5. A regular mold made of dry wood, gypsum, or resin material, in which pins made of steel or ceramics having a rectangular cross section are bundled so that the backup material can slide freely in the axial direction. It is obtained by pressing a bundle of the above pins against a model having a similar shape slightly smaller than the surface shape to give the surface shape of the backup material, then fixing the bundle from the outer periphery and casting. The epoxy resin molding die according to claim 4, which is characterized in that. 6. The epoxy resin molding die according to claim 1, wherein the molding surface has a texture pattern. 7. A thin film having an embossed pattern formed by optically treating a photo-curable resin on a molding surface, and spraying at least one fine particle of iron, sand, glass or ceramics on the thin film. A method for producing a molding die made of epoxy resin having a textured pattern on the molding surface.